The Entered Apprentice Apron.
The apron is a perfect square, its four right angles teach us that Purity, Truth, Sincerity and Honesty are the foundations of morality. Its four sides remind us to practice the four cardinal virtues - Temperance in word and deed; Fortitude in a noble purpose; Prudence in judging wisely; Justice to the humblest and greatest alike. The Square (or 'four' ) is the symbol of matter. Four was the emblem of matter to the ancients because they thought that the earth flat, square, and marked by the four points of the compass.
The flap is triangle whose three sides teach us to relieve a distressed brother. To be kind and friendly in dealing with our fellow men. The triangle is the threefold revelation for God, or Divine Wisdom.
The circle formed by the strings is the symbol of Spirit.
The Entered Apprentice Apron should have the flap pointing upwards, indicating that Divine Wisdom has not yet truly penetrated the gross matter of our bodies.
The Equilateral triangle made by the upper flap teaches us the threefold personal revelation of God. The triangle is the Symbol of the Deity for this reason. In geometry, a single line cannot represent a perfect figure, neither can two lines. Three lines, however, constiute the triangle, or first perfect demonstrable figure. Hence this figure symbolises the Eternal God, infinitely perfect in his nature. But the triangle properly refers to God only in his quality as an eternal Being, its three sides representing the past, present and future. This symbolism of the Eternal God by the triangle is the reason why the Trinitarian scheme has been so prevalent in all religions and in Freemasonry; the frequent recurrence of the No. 3 throughout all ritualistic symbolism, is striking evidence of this. The Greek character Delta is formed as an equilateral triangle and from the sacredness attached to the form of the triangle, this character was always known as the Sacred Delta. The Egyptians called it the Sacred No. 3, a number of perfection. It was an object of worship among them as a symbol of the Grand Principle of animated existence which extends its influences throughout all created matter the three sides representing the animal, vegetable and mineral departments of nature.
To the Jews the triangle represented the three periods of existence: the past, present and future. To the Hindus: creation, preservation and renewal. To the Chinese: heaven, earth and water.
The flap of the apron when raised forms a triangle standing on a square. This was considered by the Egyptians as a most perfect figure because in the Egyptian ceremony of Initiation into their mysteries, the candidate, blindfolded and with a chain around his neck, is led by a brother to a door in the wall of the temple of the lodge-the door formed a triangle symbolising Heaven and square representing the area of the entrance on which he trod symbolised earth, thus the entrance symbolised passing from Earth to Heaven. The granite triangle in the king's chamber in the Great Pyramid is said to represent the triune God of the Egyptians.
The Fellowcraft Apron
The Fellowcraft Apron has the flap pointing down and indicates (1) That wisdom has begun to enter and therefore control matter, and (2) that the Soul and body are acting in unison. The two rosettes stress the dual nature of man and have a clear reference to the two Pillars. The two rosettes also point out that the Fellowcraft has not yet completed Freemasonry as it requires a third rosette to form a triangle. It is thought by some that the blue rozettes added to the Fellowcraft apron indicate the progress being made in the science of regeneration and that the candidate's spirituality is beginning to bud forth, also that the wilderness of the natural man is now blossoming as the rose, in the flowers and graces of his regenerated nature.
The Master Mason's Apron.
The addition of the third rosette forms a triangle, pointing upwards. A triangle, point upwards, represents Fire or Divine Spark. It is the emblem of Shiva, the third member of the Hindu Trinity. It also represents spirit. The triangle of the flap and triangle of the rosettes form a square where they overlap. This square represents matter. Thus we have the union of Body (square), Soul (top triangle) and Spirit (lower triangle).